ArXiv.org, the Cornell University website that tracks scientific papers before they are published, has a record of the paper including the March 2018 update.

According to The Sunday Times, the paper sets out the mathematics necessary for a deep-space probe to collect evidence that might prove that other universes exist.

The highly theoretical work posits that evidence of the multiverse should be measurable in background radiation dating to the beginning of time. This in turn could be measured by a deep-space probe with the right sensors.

Thomas Hertog, a physics professor who coauthored the paper with Hawking, said the paper aimed "to transform the idea of a multiverse into a testable scientific framework."

Hertog, who works at KU Leuven University in Belgium, told The Sunday Times he met with Hawking in person to get final approval before submitting the paper.

The newspaper said that if such proof were ever found, it would make the scientists behind it likely candidates for a Nobel Prize.